Project Summary A major obstacle to the development of protective therapies for polycystic kidney disease (PKD) has been our limited understanding of the cellular pathways that are altered when PKD genes are mutated. In general researchers have identified critical pathways in cell culture systems and then proceeded to validate them in animal models with the goal of moving on to clinical trials. This pipeline requires a robust tool kit of basic science reagents including high quality antibodies and expression constructs. This has been particularly challenging for PKD because polycystins in particular are multi-domain membrane proteins that are difficult to work with. Many of the available antibodies lack sufficient affinity and specificity and large cDNA constructs are difficult to manipulate in cloning applications. The overarching goal of the Antibody and Vector Core is not only to supply investigators with our existing reagents, but to apply recent advances in biotechnology to develop the most innovative tools that will advance the next generation of discoveries in PKD research. This application builds on the Principal Investigator?s decades long experience in the study of polycystin biochemistry that will allow him to provide technical expertise so that investigators can fully leverage these novel reagents. In order to accomplish this goal we propose the following specific aims: 1) Maintain and provide validated PKD antibody kits that detect full length endogenous proteins 2) Use a novel strategy of whole cell immunization with cell surface PC1/PC2 to develop mouse monoclonal antibodies directed against the polycystin complex in its native configuration 3) Develop the first PC1 and PC2 Camelid VHH nanobodies using purified and stabilized PC1/PC2 complex antigen 4) Develop the first PC2 VHH nanobodies using purified and functional PC2-tetramer embedded in lipid nanodiscs and 5) Provide and develop easy-to-use vectors for PKD gene expression, inactivation and manipulation. In summary the Antibody and Vector Core will provide the research community with a comprehensive array of validated reagents and unique expertise that will facilitate discoveries in the PKD field.